The present invention relates to an antiblocking system for the driven wheels of an axle of a vehicle. More particularly, the present invention relates to an improvement in such a system in order to at least partially compensate for the mechanical coupling between two driven wheels of an axle due to the differential connected therebetween.
Torques are transmitted between the driven wheels of a vehicle as a consequence of their coupling via a differential. This is shown in FIG. 1a. There, the drive wheels are denoted by 1 and 2, the differential by 3 and the gearbox by 4. The rotational wheel speeds are denoted by .omega..sub.1 and .omega..sub.2 respectively, the braking torques by M.sub.B1 and M.sub.B2 respectively, and the drive torques by M.sub.S1 and M.sub.S2 respectively. J are the moments of inertia. FIG. 1b shows the arrangement of FIG. 1a in a representation in terms of control engineering. The variables V.sub.1 and V.sub.2 are gains. It can be seen that the difference in the torques (at 5) of each wheel passes with a gain V.sub.1 to the associated wheel, and with a different gain V.sub.2 to the other wheel where it is superimposed on the torque differential of the respective wheel (at 6). The gains V.sub.1 and V.sub.2 are specified in the form of formulae where ##EQU1##
The integrators 7 convert the torques into rotational wheel speeds .omega..sub.1 and .omega..sub.2. The slip controllers 8 influence the drive torques M.sub.S1 and M.sub.S2.
As FIG. 2 shows, these coupling torques are not considered in previous ABS control concepts. Individual wheel controllers 9 and actuators 10 for brake pressure control are represented in this figure. Block 11 here contains both the controlled system with the (internal) coupling of the two wheel torques, and the two rotational speed sensors for the drive wheels. This coupling acquires a pronounced influence particularly with the driving position engaged, and can impair the control response in ABS braking.